I have a thought. You mentioned in an earlier analysis post that Raph is the kind of guy who doesn't like interpersonal conflict and feels awkward around it. I think that I want to push back on that a bit, because its hinted that he and Leo argue a decent amount--and then especially in the movie there's a chunk of time dedicated to him and Leo arguing about responsibility--to the point where he seems to lose control, attempts to physically attack Leo and Splinter is the one who needs to stop them. (Bonus for Mikey looking disappointed in his dad for the way he handled the argument the entire scene but never saying anything to him about it). So I am thinking that when Raph believes his family could be in serious danger or actually hurt he kind of overrides that whole anxiety about conflict in the family to just...do a more classic Raph move of confronting and fighting it out rather than arguing. No?
Very good points!
Clashing with Leo about responsibility is definitely a big button, and even beyond that Raph is not afraid of similar types of confrontation. He's willing to go to bat for April by "having a friendly word" with her upstairs neighbor knocking down her ceiling fan constantly. He calls Leo out on his showboating multiple times, from The Minotaur Maze to the movie. He confronts Donnie about his addiction in the Purple Game and chews out all his brothers in Pizza Puffs when they eat poison.
So yeah, he does a lot of confronting. Perhaps conflict-averse isn't the right term. Perhaps the main difference centers around whose feelings are getting hurt, and whether or not that hurt is necessary for the greater good.
Raph strikes me as the type of Mom Friend who will go punch a landlord for being unfair to someone but struggles to tell the waiter that he got the wrong order.
In any case, it is the mark of a well-rounded character that they won't behave the exact same way in a scenario 100% of the time. There's nuance in every case. If Leo is not being receptive to talk (and, on top of that, making the situation worse by riling Raph up) then yeah, it will come to blows. If April's stomping upstairs neighbor turned out to be a, idk, a deaf child who had no idea they were making that much noise, he probably would have rolled over instantly. If Donnie had started crying or something about The Purple Game it probably would have made it harder for Raph to maintain the strength to get through to him. Heck, if Bullhop was compromising their safety or being a danger to his brothers while living in the lair, Raph probably would have thrown him out himself. As it was, a delicate conversation just needed to happen, and so Mikey and Leo were the ones to do it (and Raph still punted at the end of the episode after Bullhop helps them that he can stay, even if he clearly doesn't relish the idea).
So yeah, the degree of the conflict is definitely something to be considered. Raph is a complex person like the rest of us and it can be easy for that to get lost amongst fandom tropes and character boxes. Thank you for your ask and analysis!